A whirlpool is a violently revolving current of water. It is caused by two currents or tides meeting, by the wind blowing against a tide, by irregular conditions on the bottom, or by certain shore formations.
As the water spins, it forms a low-pressure center into which floating objects are drawn. Whirlpools form in oceans, lakes, and rivers. Famous whirlpools are the Maelstrom near Norway and Charybdis near Sicily. Though the powers of these two whirlpools are exaggerated, they are famous in legend and myth. The term "maelstrom" is another name for whirlpool.